In parts of the world, diseases such as HIV infection (and various stages of the disease), syphilis infection, malaria infection, and anemia are common and debilitating to humans, particularly to pregnant women. For example, nearly 3.5 million pregnant women are HIV-infected, and nearly 700,000 babies contract HIV from their mothers each year. These infant HIV infections can be prevented by identifying and treating mothers having HIV. In addition, nearly 20% of pregnant women in developing countries are infected with syphilis, leading to more than 500,000 infant stillbirths and deaths each year. Nearly 10,000 women and 200,000 infants die each year from malaria during pregnancy, and nearly 45% of pregnant women in developing countries suffer from anemia as a result of, for example, worm infections, parasites, and/or nutritional deficiencies. Anemia can adversely affect a pregnant woman's chance of surviving post-partum hemorrhage and stunt infant development. About 115,000 maternal deaths and 500,000 infant deaths have been associated with anemia in developing countries. Point-of-care medical diagnostic tools, however, can require one or more reagents, which must be stored in a stable environment until they are used, at which point they must be dispensed in precisely controlled volumes and flow rates.